@sagator07
Not to be a ****, but looking for the "best" tactic and disregarding the testing system at the same time seems a bit contradictory.
First of all, there's no overall "best" tactic, since it widely depends on your player material. Sure, some tactics - especially those that perform well in testing - use the match engine to their advantage very well and therefore work as plug&play tactics, even if your player material doesn't match them well.
Secondly, I get that you are probably looking to learn what kind of tactics are used in what setting and why that particular approach might do better on average. You're not gonna get that just by asking for what kind of team it was used in. If that's all you care about, I can honestly just recommend looking at the tactic testing page here as well. It's probably as objective as it can get as well.
My favored tactic at the moment is one I've actually uploaded here as well. I especially use underdog teams and see massive overperformance. That said, I'm probably a bottom half to bottom third team rather than one that's predicted to get relegated after transfers. Still, I'm fighting to win the league with my tactic.
Funnily enough, that tactic did not perform well in testing as an underdog tactic. So yeah, while I believe in the testing, you can achieve vastly different results than they did of course.
Here's my
tactic.
If you find yourself conceding loads and loads, and conceding can be a problem with this tactic at times, switching to a role that's more defensive and true to it's position than BWM, such as Anchor.
Occasionally I'm still using the first tactic I've created, which is much more stable but prone to draws if your attacking players aren't class. So
this one (
https://fm-base.co.uk/resources/mrcx-4-1-4-1-double-mezzala-the-return-of-the-king.5685/) is a tactic I'd use when I'm a second league team up against Barcelona. Although I usually turn it back to Cautious in those cases where I would take the draw but realistically look for that one counter to get them.
Actually working on a new tactic right now, will let you know when I'm happy with it and feel like it has surpassed the others.
All of these tactics are the plug&play style, though.
Depending on your team other tactics can really just outdo them. Got a keeper was 18 kicking and a 1.96m dude on the wing who's up against a 1.71 WB? Might wanna try long kicks to your WTM and knock it down to the support players. (Actually a tactic I loved in FM20 and one that should probably do better this year provided you have the correct players. Probably one that wouldn't do too well in testing if it just doesn't get those few very important attributes)